Granular and powdered food ingredients, such as salt, cheese and crushed nuts, are often applied to food products by moving the ingredients from a hopper along a horizontal tube from which they are dispensed through a series of openings. Rotation of an auger within the tube produces the lateral movement of the ingredient.
A difficult problem associated with such devices is the lack of a satisfactory provision for adjusting the rate at which the ingredient is dispensed from the tube while maintaining the uniformity of the output. It is conventional to adjust the output by varying the rotational speed of the auger, but it is generally found that with a slow rotation of the auger and a low rate of output a disproportionately small amount of ingredient reaches the end of the tube farthest from the hopper. It has also been found that a pattern of high and low ingredient density points may exist along the tube when the auger turns slowly. For example, the ingredient may emerge at alternate openings at a relatively high rate. An improved mechanism is, therefore, needed to insure both a uniform output of the ingredient throughout the length of the tube and a rate of ingredient output that can be varied over a wide range for both fine and coarse ingredients. Such a mechanism should also avoid the problem of clogging the auger with ingredient material that does not move transversely.